Numerical Investigation of Fluctuation Characters and Radial Force on Impeller within a Vortex Pump

Owing to the unique operating mechanism of the vortex pump, which differs from that of conventional vane pumps, inherent high-frequency flow fluctuations occur within the pump, leading to the natural imposition of radial forces on the impeller. The present work conducted a study on a vortex pump by numerical simulation. The numerical results are validated by comparing with experimental data. Based on the numerical calculation results, the frequency domains of pressure pulsations at several typical locations are presented. The annular interface between the rotor and the stator is developed, the characteristics of pressure and velocity pulsations including their intensity as well as the distributions of time-averaged pressure and velocity components across this interface are presented. Finally, the transient characters of the radial force acting on the impeller is studied. The results show that the numerical calculation results are in good agreement with the experimental data. The helical flow at the impeller outlet exerts a pronounced influence on the inlet-proximal regions flanking the outlet on both sides of the impeller, resulting in relatively large pressure and velocity pulsations. The induced effect of the fluid helix leads to a relatively high flow velocity on the side close to the wall surface, causing the radial velocity at the middle part of the impeller outlet to be much greater than that at other positions.